A colony of primates, Macaca fascicularis, which has been infected with S. mutans and is being fed a diet rich in sucrose, is being used to develop a vaccine against dental caries. A variety of antigens with and without adjuvant has been administered either intramucosally or intraductally. The purpose of the investigation is to determine the most appropriate antigen, the optimum route of administration, and the type of antibody response required to protect animals against caries attack.